This invention relates to halogenated 8-hydroxy quinoline compounds and methods of their preparation.
Various substituted 8-hydroxyquinolines are known in the literature. For examples, see U.S. Pat. No. 3,491,100 to Schaefer et al., U.S. Pat. No. 3,560,508 to Ruhl et al., and U.S. Pat. No. 4,520,099 to Akimura et al. Generally, these compounds correspond to the formula ##STR1## wherein X is halogen, preferably chlorine; R.sup.1, R.sup.2 and R.sup.3 are independently hydrogen, lower alkyl such as methyl, ethyl, propyl and butyl, or other non-interfering substituents; and R has various definitions as will be discussed below.
Compounds of this general formula have varying utilities depending on the nature of the R substituent. In U.S. Pat. No. 2,746,963, R has the form ##STR2## wherein R.sup.4 and R.sup.5 are independently in each occurrence alkyl or hydroxy radicals containing from 1 to 10 carbon atoms, or, when taken with ##STR3## form a saturated heterocyclic radical such as piperidino; R.sup.6 is hydrogen, methyl or ethyl; and Y is a divalent alkylene group of 2 to 5 carbon atoms. This results in a compound with therapeutic value, particularly against Endameba histolytica. In another patent, U.S. Pat. No. 4,520,099, R is preferably a second halogen atom and the compound has utility, when added to a silver halide emulsion layer, as photographic light-sensitive material in which aerial fog and spot fog are restrained. When R is a C.sub.8-20 straight or branched chain alkyl or alkenyl radical, the resulting compound is disclosed to have utility as a reagent for the liquid ion-exchange extraction of some metals, especially copper or zinc. (U.S. Pat. No. 4,065,455).
The substituted 8-hydroxyquinolines are made in varying procedures depending on the type of substituents desired. The hydroxyquinolines disclosed in U.S. Pat. No. 2,746,963 are prepared by condensing a 5-chloro-8-hydroxyquinoline with formaldehyde and an amine in an alcoholic solvent preferably with heating. U.S. Pat. No. 3,491,100 to Schaefer et al. discloses the preparation of various substituted 8-hydroxyquinolines by the condensation of 8-hydroxyquinoline with N-methylol-.alpha.-halogen-acrylamides or N-methylol-1,2-dihalogeno-proprionamides. It is disclosed in U.S. Pat. No. 3,560,508 to Ruhl et al. to prepare dichloro-8-hydroxyquinolines in a process whereby 8-hydroxyquinoline is chlorinated in chloroform with excess chlorine in the presence of iodine. The 5-halo-7-alkenyl-8-hydroxyquinolines disclosed in U.S. Pat. No. 4,065,455 are prepared by reacting a 5-halo-8-hydroxyquinoline with an alkenyl chloride in the presence of sodium hydroxide and a dimethylsulfoxide solvent with heating. The 5-halo-7-alkyl-8-hydroxyquinolines also disclosed in U.S. Pat. No. 4,065,455 are prepared by reacting an 8-hydroxyquinoline with an alkenyl chloride as above with subsequent hydrogenation and halogenation.
While it is known how to prepare a number of substituted 8-hydroxyquinolines, a problem exists in that not all substituted 8-hydroxyquinolines can be prepared by these known methods. Further, it is desirable to produce novel compounds comprising 8-hydroxyquinolines with utility in the preparation of ion-exchange resins.